This invention relates generally to fiber optic connectors and, more specifically, to a separable in-line fiber optic connector for coupling a pair of fiber optic cables or a single fiber optic cable and a light source or detector. The terminal end surface of an inner fiber core for use in lightwave transmission must be flat and highly polished to minimize insertion losses. The inner fiber core typically must also be axially, laterally, and angularly aligned within certain parameters to establish an excellent optical coupling between two fiber optic cables. The success achieved in the development and production of fiber optic cables has therefore focused strongly upon low loss connectors and couplers for such cables including in-line connectors. The ability to design, manufacture, deploy and service a data transmission line, for instance, requires suitable connectors in order to assure the continued progress of the fiber optics field. Accordingly, connectors for this and other applications must be developed which can be used without any significant increase in insertion losses.
Many fiber optic connectors presently available are precision, expensive instruments providing very low insertion losses but they are designed for certain applications such as long distance applications in telephonic systems and in other applications reguiring extremely low insertion losses where expensive low loss connectors may be employed. It has been found, however, that expensive low loss connectors are not always well suited for applications requiring a large number of connectors where very expensive connectors are not economically feasible. For instance, in such applications as computers and other data transmission applications, a large number of fiber optic cables are employed and there is a need for low cost, low loss fiber optic connectors which minimize insertion losses due to off-centering of the fiber core relative to the connector or terminal member. It is well known in such applications to use low cost fiber optic cables in which the inner fiber core is often not concentric with the outer coating or cladding. Of course, this non-concentricity has a tendency to lead to excessive insertion losses when a connector that utilizes the outer coating or cladding as a jigging surface is put into a data transmission line.
As stated above, alignment of the fiber core is important to minimize insertion losses, but most connectors which are effective to properly position or center the core with respect to the mating terminal end of the connector or terminal member are very expensive instruments. This invention is directed to solving these problems by providing a new and improved fiber optic connector and means and method of centering or properly positioning optical fibers or inner fiber cores of fiber optic cables with respect to the mating terminal end of the connector.